The present invention relates to a friction reducing tool suitable for use in drilling applications. In one aspect the present invention relates to a tool having a multipart rotatable outer component wherein the parts may be secured together by rods insertable through a groove in the main body part of the drill string component and a tool incorporating rollers having positive roller containment.
It is known in the industry to provide a tool in which an outer rotatable portion is formed in multiple parts, which are secured together about the tool. Typically, a recess is provided in the main body portion of the tool and the multiple parts are secured about the main body portion within the recess so as to be rotatable thereabout. Typically, the multiple portions are fastened together by bolts or other similar fastening means. Often this requires projecting flanges which may cause obstruction. Further, under extreme loads the multiple portions could separate, leaving parts of the tool obstructing a well.
It is also known to provide rollers about the periphery of a tool to minimise friction. Typically, such rollers are inserted into a cavity in the tool from the exterior and a pin is inserted to secure the roller in place. Under severe load conditions the pin can shear and the roller and pin may drop out of the tool and obstruct the well.
It is an object of the present invention to overcome these problems or at least to provide the public with a useful choice.
According to a first aspect of the invention there is provided a friction reducing tool for drilling applications comprising a generally tubular body portion having a cavity in a side wall thereof which accommodates a roller, wherein the cavity is dimensioned so that the roller can be introduced into the cavity from the interior of the body portion but cannot pass out of the cavity to the exterior of the body portion.
According to a further aspect of the invention there is provided a friction reducing tool having an inner component securable to or about a drill string and an outer component rotatable about the inner component, wherein the outer component is formed in multiple parts secured together by rods and is located within an annular recess in the inner component and wherein a groove is provided in the inner component adjacent the recess to enable a rod to be inserted when the parts of the outer component are assembled about the recess.
The groove is preferably angled downwardly towards the recess so that the rod deflects as it is inserted into apertures in the parts and, when in place, abuts against thrust faces of the drill string component.
According to a further aspect there is provided a friction reducing tool comprising a plastic sleeve for securement about a drill pipe, first and second collars to secure the plastic sleeve to a drill pipe at either end thereof and an outer component for securement about the plastic sleeve between the collars, wherein the outer component is provided with a plurality of friction reducing rollers about the periphery thereof.